Comparative study on the alteration geochemical characteristics of Xiadian Gold Deposit and Dayingezhuang Gold Deposit in Jiaodong Peninsula
Dayingezhuang Gold Deposit and Xiadian Gold Deposit are typical"Jiaojia-type"fractured zone alteration rock gold deposits within the Zhaoping Fault.Sequential alterations from the fault outward include beresitization alteration and K-feldspar alteration.However,differences in alteration-related element migration between the 2 deposits have received limited attention.This study conducted detailed petrographic,mineralogical,and geochemical investigations.K-feldspar alteration at Xiadian Gold Deposit is characterized by Fe2O3 and K2O enrichment,indicating a composite alteration involving potassium feldspar replacing plagioclase with iron-bearing mineral inclusions.In contrast,the K-feldspar alteration at Dayingezhuang Gold Deposit is a composite alteration of albite-sericite-potassium feldspar,showing K2O enrichment alongside Na2O and Fe2O3 depletion.Both deposits'K-feldspar alteration rocks are enriched in gold-associated elements,but Xiadian Gold Deposit shows As depletion,whereas Dayingezhuang Gold Deposit exhibits Zn and Cd depletion.Beresitization alteration at Dayingezhuang Gold Deposit enriches K2O,Fe2O3,MgO,and LOI,while Xiadian Gold Deposit exhibits depletion in K2O,CaO,MgO,and TiO2.These differences suggest stronger chloritization and sericitization at Dayingezhuang Gold Deposit,potentially caused by the breakdown of mafic minerals and plagioclase in amphibolite in water-rock reactions,increasing K2O and MgO content in fluids.Gold migration during beresitization alteration is less pronounced at Xiadian Gold Deposit compared to Dayingezhuang Gold Deposit,likely due to buffering effects from marble water-rock reactions in the Jingshan Group,stabilizing fluid pH and inhibiting gold-sulfur complex breakdown and deposition.
wall rock alterationalteration geochemical characteristicsK-feldspar alterationberesitizationmass balancefractured zonealteration rock gold depositJiaodong
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